| Fixer Consultancy Limited | Professional & scientific | 2016 |
| Fixfirst Ltd | Construction | 2025 |
| Fixmyline Ltd | Information & communication | 2018 |
| Fizzi Jumps Ltd | Manufacturing | 2019 |
| FJR Plumbing & Heating Limited | Construction | 2017 |
| FJS Group Holdings Ltd | Financial services | 2026 |
| FJS Investments Ltd | Financial services | 2026 |
| Flashback Consultants UK Limited | Administrative & support | 2016 |
| Flav B Limited | Transport & logistics | 2017 |
| Flava Cuisine Ltd | Hospitality | 2025 |
| Fleet Street Barristers Direct Ltd | Professional & scientific | 2022 |
| Fleetrax Ltd | Transport & logistics | 2024 |
| Fleming Education Ltd | Information & communication | 2022 |
| Fleur DE the Ltd | Hospitality | 2013 |
| Flip and Stick Ltd | Education | 2021 |
| Flo's Fancies Limited | Wholesale & retail | 2011 |
| Flo-Ozone Limited | Administrative & support | 2024 |
| Float Right Limited | Information & communication | 2010 |
| Floatin Buka Ltd | Hospitality | 2020 |
| Floatzees Ltd | Wholesale & retail | 2026 |
| Flomendis Mechanical Services Ltd | Construction | 2026 |
| Floorcraft Sidcup Ltd | Construction | 2024 |
| Floots Ltd | Manufacturing | 2013 |
| Flori Properties Limited | Real estate | 2025 |
| Flot Ltd. | Manufacturing | 2019 |
| Flotek Ltd | Construction | 2023 |
| Flotun Group Ltd | Professional & scientific | 2025 |
| Flour & Flower London Ltd | Hospitality | 2024 |
| Floura Limited | Information & communication | 2025 |
| Flovara Limited | Administrative & support | 2025 |
| Flow Matic Limited | Construction | 2024 |
| Flow ‘N’ Go Limited | Administrative & support | 2025 |
| Flowfix Drainage Ltd | Administrative & support | 2026 |
| Flowstop Engineering Limited | Manufacturing | 2017 |
| Flowstop Services Limited | Construction | 2000 |
| Floyd Management Limited | Households | 2020 |
| Floyd on Fones Limited | Information & communication | 2013 |
| Flying Dove Theatre Limited | Arts & recreation | 2023 |
| FM Group Services Ltd | Construction | 2018 |
| FM Kitchen Ltd | Hospitality | 2025 |
| FM Property & Facility Management Ltd | Real estate | 2023 |
| FM3 Limited | Administrative & support | 2025 |
| Fmhenry Ltd | Professional & scientific | 2013 |
| Fmhenry Properties Ltd | Real estate | 2024 |
| Fmit Partners Limited | Information & communication | 2010 |
| Fmmf Limited | Wholesale & retail | 2017 |
| Fmns Holdings Limited | Financial services | 2021 |
| FNC Recruitment Ltd | Administrative & support | 2023 |
| Fnpharma Ltd | Health & social care | 2022 |
| Foclean Ltd | Wholesale & retail | 2025 |
| Focus Controls Ltd. | Construction | 2010 |
| FOCUS25 Ltd | Professional & scientific | 2022 |
| Folfar Estate Ltd | Real estate | 2016 |
| Folfar Living Care Services Ltd | Health & social care | 2018 |
| Folly Victory Limited | Professional & scientific | 2018 |
| Food Soldiers Ltd | Professional & scientific | 2022 |
| Foood Ltd | Health & social care | 2015 |
| Forael Limited | Real estate | 2025 |
| Fore Security Solutions Ltd | Administrative & support | 2020 |
| Foreman Enterprises Limited | Extraterritorial | 2008 |
| Forensic Inquiry & Taxation Services Ltd | Administrative & support | 2026 |
| Forensic, Investigations and Taxation Services Ltd | Professional & scientific | 2017 |
| Forever Care Agency Ltd | Administrative & support | 2021 |
| Forge Lifts Ltd | Manufacturing | 2021 |
| Forge Longevity Ltd | Arts & recreation | 2024 |
| Forged INK Co Limited | Manufacturing | 2026 |
| Forgekind Limited | Financial services | 1992 |
| Fork and Finance Limited | Professional & scientific | 2024 |
| Formation Management Ltd | Construction | 2018 |
| Formations Online Limited | Extraterritorial | 2011 |
| Formulate Recruitment Ltd | Administrative & support | 2019 |
| Fornidon Ltd | Construction | 2005 |
| Forrester Dobson Ltd | Construction | 2023 |
| Forsythe Shades (Beckenham) Management Limited | Households | 1980 |
| Fort Knight Limited | Real estate | 1981 |
| Forte Staffing Ltd | Administrative & support | 2026 |
| Fortify Roofing Ltd | Construction | 2026 |
| Fortis Signum Ltd | Administrative & support | 2023 |
| Fortium Group Ltd | Real estate | 2026 |
| Fortuna Bay Trading Company Limited | Real estate | 2017 |
| Fortune 369 Limited | Wholesale & retail | 2021 |
| Fortune Haven Properties Ltd | Real estate | 2025 |
| Fortune Media Group (UK) Limited | Financial services | 2018 |
| Forty Five High Street Ltd | Construction | 2020 |
| Forum for International Relations Limited | Other services | 2016 |
| Forza Construction Ltd | Administrative & support | 2020 |
| Foshdav Consulting Limited | Financial services | 2013 |
| Fosker Investments Ltd | Real estate | 2019 |
| Foster's Mews Limited | Households | 2003 |
| FOT Fire Control & Equipment Limited | Manufacturing | 2024 |
| Fotej Ltd | Professional & scientific | 2026 |
| Fotude Ltd | Professional & scientific | 2021 |
| Foundry Unknown Ltd | Wholesale & retail | 2025 |
| Fountain Displays Limited | Administrative & support | 2007 |
| Four Chain Holding Ltd | Construction | 2022 |
| Four OS Consulting Ltd | Professional & scientific | 2014 |
| Four Pillars (Kent) Ltd | Real estate | 2022 |
| Four Seasons Supplies Ltd | Wholesale & retail | 2026 |
| FOX Estate Agents Ltd | Real estate | 2010 |
| Foxmans Construction Ltd | Construction | 2021 |